JP2012106581A - Vehicular energy storage protection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable continuous travel of a vehicle while effectively avoiding overvoltage of an energy storage even if abnormality of a voltage sensor for detecting voltage of the energy storage occurs, in a vehicular energy storage protection system.SOLUTION: A rotating electrical machine drive system 30 as the vehicular energy storage protection system includes: a DC/DC convertor 42 for boosting the voltage of a battery 16; a control part 36; a first voltage sensor 50 for detecting inter-terminal voltage of the battery 16; and a second voltage sensor 52 and a third voltage sensor 54 for detecting voltages of a low voltage side and a high voltage side of the DC/DC converter 42. The control part 36 includes: a means for acquiring current SOC of the battery 16; a means for setting control center SOC as a control center when the charge amount of the battery 16 is controlled; and a means for making the current control center SOC lower than the control center SOC at normal time if occurrence of abnormality in the first voltage sensor 50 is determined.

Description

  The present invention relates to a power storage unit for a vehicle that includes a power storage unit, a boost converter that boosts the voltage of the power storage unit, a drive unit that is supplied with a voltage on the high voltage side of the boost converter and drives a traveling motor, and a plurality of voltage sensors. Department protection system.

  2. Description of the Related Art Conventionally, a hybrid vehicle, which is an electric vehicle equipped with an engine and a traveling motor and drives wheels using at least one of the engine and the traveling motor as a drive source, has been considered and implemented. For example, Patent Document 1 discloses a battery that is a power storage unit, a boost converter that boosts the voltage of the battery, an inverter that is supplied with a voltage on the output side of the boost converter, and drives a motor generator that is a running motor, and a control The vehicle drive device provided with a part is described.

  Further, the vehicle drive device detects a voltage value output from the battery, a first voltage sensor that detects a voltage on the output side of the boost converter, and a voltage on the input side of the boost converter. A second voltage sensor is provided. In addition, when an abnormality occurs in the first voltage sensor, the control unit gives an instruction to stop the operation of the boost converter and cause the inverter to perform a power running operation of the rotating electrical machine, and connects to the output side of the boost converter. The discharged capacitor is discharged.

  Further, in Patent Document 1, when a failure occurs in the voltage sensor that detects the voltage on the output side of the boost converter, the boost control of the boost converter is stopped, and the battery voltage is supplied to the inverter as it is without being boosted. It describes that the vehicle continues to run.

JP 2006-325322 A

  In the case of the configuration described in Patent Document 1 described above, the vehicle can be run even when the first voltage sensor that detects the voltage on the output side of the boost converter fails. However, in the configuration of Patent Document 1, it is not considered that the vehicle can be continuously driven even when a battery voltage sensor that detects the voltage of the battery fails.

  On the other hand, the input-side voltage sensor that detects the voltage on the input side of the boost converter detects the battery voltage even when the battery voltage sensor fails, and performs predetermined high-voltage processing when the detected voltage becomes abnormally high. It is possible to do it. However, since the detection accuracy of the input side voltage sensor is not required to be as high as the detection accuracy of the battery voltage sensor during normal operation, the battery voltage can be detected accurately when the battery voltage sensor fails. It becomes difficult. For this reason, even when the battery voltage sensor fails, there is room for improvement from the aspect of enabling the vehicle to continue running while effectively avoiding the battery overvoltage, that is, while effectively protecting the battery overvoltage. In particular, in recent years, lithium batteries have begun to be used as batteries for hybrid vehicles. In such lithium batteries, it is important to avoid overvoltage from the viewpoint of suppressing battery deterioration.

  An object of the present invention is to enable continuous running of a vehicle while effectively avoiding an overvoltage of a power storage unit even when an abnormality of a voltage sensor that detects the voltage of the power storage unit occurs in a vehicle power storage unit protection system. It is.

  A power storage unit protection system for a vehicle according to the present invention includes a power storage unit, a boost converter that boosts the voltage of the power storage unit, a drive unit that is supplied with a voltage on the high voltage side of the boost converter, and drives a traveling motor, and a power storage unit A first voltage sensor for detecting a voltage between the terminals of the boost converter, a low-voltage side voltage of the boost converter, a second voltage sensor used for controlling the boost converter, and a high-voltage side voltage of the boost converter A third voltage sensor that detects and uses the detected voltage to control the boost converter; an SOC acquisition means that acquires a current SOC that is a current charge amount of the power storage unit; and a control unit that controls the charge amount of the power storage unit A setting means for setting a control center SOC, which is a charge amount serving as a control center, a charge / discharge request means for making a charge / discharge request for the power storage unit so that the current SOC of the power storage unit approaches the control center SOC, and a first voltage A first sensor that obtains the detected value of the voltage of the power storage unit from the second voltage sensor and lowers the current control center SOC from the normal control center SOC when it is determined that an abnormality has occurred in the sensor. A vehicle power storage unit protection system comprising an abnormality processing unit.

  According to the vehicle power storage unit protection system of the present invention, the first sensor abnormality processing means detects the voltage of the power storage unit from the second voltage sensor when the abnormality of the first voltage sensor that detects the voltage of the power storage unit is detected. Since the value is acquired, the voltage of the power storage unit can be monitored by the detection value of the second voltage sensor. For this reason, when the detected voltage is abnormally high voltage, preset specific processing such as battery high voltage processing can be performed. Further, the travel motor can be driven using a voltage obtained by boosting the voltage of the power storage unit, and the vehicle can be continuously traveled using the travel motor. Further, the first sensor abnormality processing means makes the current control center SOC lower than the normal control center SOC. For this reason, it is possible to effectively suppress the SOC of the power storage unit from exceeding the allowable upper limit even though the second voltage sensor that does not require high voltage detection accuracy during normal use is used for voltage detection of the power storage unit. The SOC of the power storage unit greatly affects the voltage of the power storage unit. Therefore, even when an abnormality occurs in the voltage sensor that detects the voltage of the power storage unit, the vehicle can continue to travel while avoiding the overvoltage of the power storage unit.

  In the vehicular power storage unit protection system according to the present invention, preferably, the first sensor abnormality processing means determines that the current control center SOC is normal when it is determined that an abnormality has occurred in the first voltage sensor. When the vehicle travels when the first voltage sensor is detected abnormally or after the abnormality is detected, the maximum value of chargeable / dischargeable power for the power storage unit is set to the maximum value of normal chargeable / dischargeable power. Lower than.

  According to the above configuration, even when the first voltage sensor is abnormal, it is possible to avoid the overvoltage of the power storage unit by using the second voltage sensor that does not require high voltage detection accuracy during normal time, and the time when the use of the power storage unit is not limited And a sudden change in the running performance of the vehicle can be suppressed.

  In the vehicle power storage unit protection system according to the present invention, preferably, when it is determined that an abnormality has occurred in the first voltage sensor, the current control center SOC is made lower than the normal control center SOC. When the vehicle travels when an abnormality is detected in the first voltage sensor or after the abnormality is detected, the maximum value of the chargeable / dischargeable power for the power storage unit is decreased below the maximum value of the chargeable / dischargeable electric power at the normal time. When charging the power storage unit when the abnormality is detected or after the abnormality is detected, the maximum value of the chargeable / dischargeable power for the power storage unit is maintained as it is.

  According to the above configuration, even when the first voltage sensor is abnormal, it is possible to avoid the overvoltage of the power storage unit by using the second voltage sensor that does not require high voltage detection accuracy during normal time, and the time when the use of the power storage unit is not limited And a sudden change in the running performance of the vehicle can be suppressed. Furthermore, since charging / discharging electric power is not restrict | limited at the time of charge in a vehicle stop state, charging efficiency can be made high.

  In the vehicle power storage unit protection system according to the present invention, preferably, when it is determined that an abnormality has occurred in the first voltage sensor and the second voltage sensor, the operation of the boost converter is stopped, and the third voltage sensor The second sensor abnormality time processing means is provided for acquiring a detected value of the voltage of the power storage unit from the power source and executing a preset power storage unit high-voltage process when the detected voltage exceeds a preset threshold value.

  According to the above configuration, even when an abnormality occurs in the second voltage sensor, the voltage of the power storage unit can be monitored by the detection value of the third voltage sensor, so that an overvoltage of the power storage unit can be avoided. Further, the travel motor can be driven using the voltage of the power storage unit, and the vehicle can be continuously traveled using the travel motor.

  In the vehicle power storage unit protection system according to the present invention, preferably, when it is determined that an abnormality has occurred in all of the first voltage sensor, the second voltage sensor, and the third voltage sensor, the power storage unit is charged and discharged. A third sensor abnormality processing means for stopping the operation.

  In the vehicle power storage unit protection system according to the present invention, preferably, the power storage unit is configured by connecting a plurality of battery blocks each having a plurality of battery cells connected in series, and the first voltage sensor includes A plurality of block voltage sensors for detecting the voltage of the battery block; the total voltage of each battery block detected by each block voltage sensor is detected as a voltage across the terminals of the power storage unit; and the second voltage sensor and the third voltage Each sensor has a detection accuracy lower than the detection accuracy of the first voltage sensor.

  According to the vehicle power storage unit protection system of the present invention, even when an abnormality occurs in the voltage sensor that detects the voltage of the power storage unit, the vehicle can continuously travel while avoiding overvoltage of the power storage unit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating a configuration of a hybrid vehicle including a rotating electrical machine drive system that is an example of a power storage unit protection system for a vehicle according to an embodiment of the present invention. It is a figure which shows the structure of the rotary electric machine drive system mounted in the vehicle of FIG. It is a figure which shows the structure of the control part of FIG. FIG. 3 is an SOC state diagram of a battery showing an example of a relationship between a control center SOC and an allowable upper limit and an allowable lower limit in a normal state (A) and a first voltage sensor failure (B) in the system of FIG. 2. . In the system of FIG. 2, it is a figure which shows an example of the relationship between SOC of a battery, chargeable electric power Win, and dischargeable electric power Wout in the normal time and the time of a 1st voltage sensor failure. 3 is a flowchart illustrating an example of a method for executing battery high voltage processing based on detection values of a first voltage sensor and a second voltage sensor in the system of FIG. 2.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. 1 to 6 show an example of an embodiment of the present invention. In the following description, a case where the vehicle power storage unit protection system is mounted on a hybrid vehicle will be described, but the present invention is not limited to the configuration used for such applications, and a traveling motor and a battery are provided. It can also be used by being mounted on another electric vehicle such as an electric vehicle provided.

  A rotating electrical machine drive system that is a vehicle power storage unit protection system according to the present embodiment is used by being mounted on a hybrid vehicle. As shown in FIG. 1, the hybrid vehicle 10 is driven by an engine 12, a first motor generator (MG1) 14 that is driven by the engine 12 and is mainly used as a generator, and a battery 16 that is mainly supplied with electric power. A second motor generator (MG2) 18 that is a motor, a power split mechanism 20, and a wheel 24 connected to a drive shaft 22 are provided.

  FIG. 1 shows a case where the hybrid vehicle 10 is an FF vehicle that is a front-wheel drive vehicle with a front engine. However, the hybrid vehicle may be an FR vehicle that is a rear wheel drive vehicle with a front engine, a 4WD vehicle that is a four wheel drive vehicle, or the like.

  The power split mechanism 20 can split the power from the engine 12 into a path to the drive shaft 22 and a path to the first motor generator 14. The power split mechanism 20 is configured by, for example, a planetary gear mechanism. For example, the rotation shaft of the first motor generator 14 is hollow, and the sun gear of the planetary gear mechanism is connected to the end of the rotation shaft. Further, the carrier connected to the planetary gear of the planetary gear mechanism is connected to the drive shaft of the engine 12 inserted through the inside of the rotation shaft of the first motor generator 14. Further, the output shaft 26 is connected to the ring gear of the planetary gear mechanism, and the rotation shaft of the second motor generator 18 is connected to the output shaft 26 directly or via a speed reducer such as another planetary gear mechanism (not shown). The power of the output shaft 26 can be transmitted to the drive shaft 22 connected to the wheel 24 via the speed reducer 28.

  The first motor generator 14 is a three-phase AC motor and can also be used as a starting motor for the engine 12. However, when the first motor generator 14 is used as a generator driven by the engine 12, the engine 12, at least part of the torque transmitted through the carrier of the planetary gear mechanism is transmitted to the rotation shaft of the first motor generator 14 through the sun gear.

  The second motor generator 18 is a three-phase AC motor for generating a driving force of the vehicle, and can also be used as a generator, that is, for power regeneration.

  The rotation of the engine 12 is extracted to the output shaft 26 side and the first motor generator 14 side via the power split mechanism 20. The electric power generated by driving the first motor generator 14 is charged in the battery 16 that is a power storage unit. Note that the configuration of the hybrid vehicle 10 is not limited to such a configuration, and various configurations may be used as long as the hybrid vehicle 10 has a configuration of a hybrid vehicle that travels using at least one of an engine and a motor generator as a wheel drive source. Can be adopted.

  Next, the rotating electrical machine drive system provided in the hybrid vehicle 10 will be described. As shown in FIG. 2, the rotating electrical machine drive system 30 includes the battery 16 and the motor generators 14 and 18, a battery monitoring unit 32, a battery ECU (Electric Control Unit) 34, a control unit 36, A first inverter 38 that is a drive unit for the motor generator 14, a second inverter 40 that is a drive unit for the second motor generator 18, and the first inverter 38, the second inverter 40, and the battery 16 are connected. DC / DC converter 42 which is a step-up converter, first capacitor 44 and second capacitor 46, system relay (SMR) 48, first voltage sensor 50, second voltage sensor 52 and third voltage sensor 54 and current. Sensor 56.

  The battery 16 is a secondary battery such as a nickel metal hydride battery or a lithium ion battery. The battery 16 is called a battery pack configured by connecting a plurality of battery blocks each having a plurality of battery cells connected in series.

  Further, the rotating electrical machine drive system 30 is provided with a first voltage sensor 50 that detects the voltage across the terminals of the battery 16, and the detected voltage of the first voltage sensor 50 is input to the battery ECU 34 via the battery monitoring unit 32. Is done. The first voltage sensor 50 includes a plurality of block voltage sensors (not shown) that can detect the voltage of the corresponding battery block, and a plurality of cell voltage sensors that can detect the voltage of each battery cell constituting each battery block. (Not shown). Further, the first voltage sensor 50 can detect the sum of the voltages of the battery blocks detected by the block voltage sensors as the inter-terminal voltage VB of the battery 16. The first voltage sensor 50 is not limited to the one constituted by a plurality of voltage sensors as described above, and may be configured to detect the entire voltage of the battery 16 by a single voltage sensor VB. it can.

  Further, the present invention aims to avoid overcharging of the battery 16, and is particularly effective when the battery 16 is a lithium ion battery. The battery 16 may be configured to be chargeable from an external AC power supply by an external charging configuration. For example, a charging cable connected to a commercial power supply outside the vehicle can be connected to a charging inlet provided on the vehicle side, and the charging inlet can be connected to the battery 16 via a charger or the like. In this case, the battery 16 can be externally charged by the external power source. Such a hybrid vehicle is called a plug-in hybrid vehicle (PHV).

  The battery monitoring unit 32 receives the voltage of each block of the battery 16 detected by the first voltage sensor 50 and the voltage VB of the entire battery 16, and the input voltage of each block of the battery 16 and the entire battery 16. Is output to the battery ECU 34. In addition, the battery monitoring unit 32 receives the current of the battery 16 detected by the current sensor 56 and outputs the input current to the battery ECU 34. Alternatively, the voltage for each block of the battery 16 from the first voltage sensor 50 may be input to the battery monitoring unit 32, and the battery monitoring unit 32 may calculate the total voltage for each block as VB.

  The battery ECU 34 calculates, that is, obtains an SOC (State Of Charge) that is a charge amount of the battery 16 from the voltage VB of the entire battery 16 input from the battery monitoring unit 32 and the input current, and obtains the calculated SOC. Output to the control unit 36. Note that the battery monitoring unit 32 and the battery ECU 34 may be integrated by a single unit.

  Further, the control unit 36 includes an SOC acquisition unit 58 (FIG. 3), and the SOC acquisition unit 58 acquires the SOC from the battery ECU 34. That is, the SOC acquisition means 58 acquires the current SOC that is the current charge amount of the battery 16. The SOC acquisition means 58 can also input data such as the voltage VB of the entire battery 16 and the input current from the battery monitoring unit 32 or the battery ECU 34, and calculate, that is, acquire the SOC from the data. As a method for calculating the SOC, a known method such as using a correlation between the open circuit voltage, which is the OCV of the battery 16, and the SOC, or integrating the charge / discharge current of the battery 16 can be employed.

  The DC / DC converter 42 is provided between the battery 16 and the first inverter 38 and the second inverter 40. The DC / DC converter 42 includes two switching elements S1 and S2 such as IGBTs and transistors connected in series, two diodes D1 and D2 connected in antiparallel to the switching elements S1 and S2, and each switching element. A reactor L having one end connected between the elements S1 and S2, and the other end of the reactor L is connected to the positive electrode side of the battery 16 via one system relay 48. The DC / DC converter 42 can boost the DC voltage supplied from the battery 16 and supply it to the first inverter 38 and the second inverter 40. Further, the DC / DC converter 42 has a function of stepping down a DC voltage supplied from one or both of the two inverters 38 and 40 and supplying DC power to the battery 16, that is, charging the battery 16.

  In addition, a first capacitor 44 for current smoothing is provided on the low voltage side of the DC / DC converter 42, that is, on the battery 16 side. Further, the voltage between the terminals of the first capacitor 44, that is, the voltage on the low voltage side of the DC / DC converter 42, is closer to the DC / DC converter 42 than the system relay 48 described later between the DC / DC converter 42 and the battery 16. A second voltage sensor 52 is provided for detecting. A second capacitor 46 for current smoothing is provided on the high voltage side of the DC / DC converter 42, that is, on each inverter 38, 40 side. Further, the rotating electrical machine drive system 30 is provided with a third voltage sensor 54 that detects the voltage across the terminals of the second capacitor 46, that is, the voltage on the high voltage side of the DC / DC converter 42. Detection voltages VL and VH of the second voltage sensor 52 and the third voltage sensor 54 are input to the control unit 36.

  The DC / DC converter 42 is controlled by the control unit 36. That is, the control unit 36 includes a boost control unit 60 (FIG. 3). The boost control unit 60 is configured to control the DC / DC converter 42 based on the detection voltages of the second voltage sensor 52 and the third voltage sensor 54. Controls operation, ie switching. That is, the detection voltages VL and VH of the second voltage sensor 52 and the third voltage sensor 54 are used for controlling the DC / DC converter 42. The second voltage sensor 52 and the third voltage sensor 54 have detection accuracy lower than the detection accuracy of the first voltage sensor 50, respectively.

  A system relay 48 is provided between the battery 16 and the DC / DC converter 42, and the system relay 48 is controlled to be turned on and off by the control unit 36. That is, when a start switch (not shown) is turned on by the user, the control unit 36 is started, the control unit 36 turns on the system relay 48, and the DC voltage of the battery 16 is boosted. 2 is supplied to the inverter 40. When the start switch is turned off, the system relay 48 is turned off, and the connection between the battery 16 and the first inverter 38 and the second inverter 40 is cut off.

  Moreover, the inverters 38 and 40 are provided with arms for U, V, and W phases. Each arm includes two switching elements such as IGBTs and transistors connected in series, and the middle point of each arm is a three-phase stator coil (not shown) constituting the corresponding motor generator 14 (or 18). Each is connected to one end. The two inverters 38 and 40 are connected to the battery 16 in parallel. In each motor generator 14, 18, the other ends of the three-phase stator coils are connected to each other at a neutral point.

  Each of the inverters 38 and 40 receives the control signal corresponding to the torque command value from the control unit 36, thereby controlling the switching of each switching element. For example, the first inverter 38 converts the DC voltage input from the battery 16 side into an AC voltage based on a signal corresponding to the torque command value input from the control unit 36 and drives the first motor generator 14. . In addition, when the first motor generator 14 generates power as the engine 12 (FIG. 1) is driven, the first inverter 38 converts the AC voltage obtained by the power generation into a DC voltage by the first inverter 38. The converted DC voltage is supplied to the DC / DC converter 42. The DC / DC converter 42 steps down the supplied DC voltage and then supplies it to the battery 16 to charge the battery 16.

  On the other hand, the second inverter 40 converts the DC voltage input from the battery 16 side into an AC voltage based on a signal corresponding to the torque command value input from the control unit 36, and the second motor generator. 18 is driven. The second inverter 40 also converts the AC voltage generated by the second motor generator 18 into a DC voltage during regenerative braking of the hybrid vehicle 10 (FIG. 1), and converts the converted DC voltage to the DC / DC converter 42. Supply. The DC / DC converter 42 steps down the supplied DC voltage and then supplies it to the battery 16 to charge the battery 16. Regenerative braking is executed when the accelerator pedal of the vehicle is not depressed and the battery 16 has a small amount of charge. Thus, the inverters 38 and 40 are supplied with the voltage on the high voltage side of the DC / DC converter 42 and drive the corresponding motor generators 14 and 18.

  The control unit 36 includes a microcomputer having a CPU, a memory, and the like, and may include, for example, a motor controller called a motor ECU and an engine controller called an engine ECU. In the illustrated example, only one control unit 36 is illustrated as the control unit 36, but the control unit 36 may be appropriately divided into a plurality of components and connected to each other. For example, the control unit 36 may be divided into a part having a function of a motor controller, a part having a function of an engine controller, and an overall control part that integrally controls the whole called a hybrid ECU, and may be connected to each other. .

  The control unit 36 receives detection signals from various sensors such as an accelerator operation amount sensor, a vehicle speed sensor, and a brake pedal sensor. The accelerator operation amount sensor detects an operation amount of an acceleration instruction tool such as an accelerator pedal. The vehicle speed sensor detects the speed of the vehicle. The brake pedal sensor detects an on / off state of a braking instruction tool such as a brake pedal. The control unit 36 calculates an output required for the entire vehicle from these signals and a charge / discharge request of the charge / discharge request means 62 (FIG. 3) described later, and outputs the output to an engine output and a motor output. The distribution ratio is calculated, and the torque command value and the power generation amount command value of the motor generators 14 and 18 corresponding to the motor output are calculated, that is, acquired. Further, the control unit 36 has a motor current value flowing through the stator coil of each phase of each of the motor generators 14 and 18 detected by a current sensor (not shown) provided in the first motor generator 14 and the second motor generator 18. In addition, signals representing the rotation angles of the motor generators 14 and 18 are also input.

  The control unit 36 outputs a control signal to the second inverter 40 in accordance with the calculated torque command value for the second motor generator 18, and turns on / off the switching elements constituting the second inverter 40 in accordance with the control signal. That is, a switching operation is performed. Then, the control unit 36 drives the second motor generator 18 so that the second motor generator 18 outputs a torque according to the torque command value. Similarly, the control unit 36 outputs a control signal to the first inverter 38, performs switching operation of the switching elements constituting the first inverter 38 in accordance with the control signal, and the first motor generator 14 calculates the first The first motor generator 14 is driven so that torque according to the torque command value for the one motor generator 14 is output. Such a hybrid vehicle 10 is driven using at least one of the engine 12 and the second motor generator 18 as a drive source.

  In addition, the control unit 36 determines in advance that the brake pedal is turned off during traveling, that is, the operation amount becomes 0, according to the calculated power generation amount command value for the second motor generator 18 or the first motor generator 14. A control signal is output to the corresponding inverter 40 (or 38) on condition that the set specific condition is satisfied, and the corresponding inverter 40 (or 38) is switched according to the control signal.

  The configuration of the control unit 36 will be described with reference to FIG. In the following description, the same elements as those shown in FIG. The control unit 36 sets the control center SOC, which is the SOC serving as the control center when controlling the SOC of the battery 16, and the charge / discharge of the battery 16 so that the current SOC of the battery 16 approaches the control center SOC. Charge / discharge requesting means 62 for performing control. For example, FIG. 4 is a battery showing an example of the relationship between the control center SOC and the allowable upper limit and the allowable lower limit at the normal time (A) and when the first voltage sensor fails (B) in the system of FIG. FIG. As shown in FIG. 4, the battery 16 has an allowable upper limit that is a charging limit and an allowable lower limit that is a discharging limit for each SOC. For example, the allowable lower limit is between 20 and 30% of the total charging capacity. In any value, the allowable upper limit is a value around 80% of the total charge capacity. The “allowable upper limit” is the upper limit SOC that causes the battery 16 to be overcharged and cause performance problems such as characteristic deterioration if the charging is continued further. In particular, when the battery 16 is a lithium ion battery, overcharging causes the temperature to rise excessively, so it is highly important to prevent the SOC from increasing beyond the “allowable upper limit”. On the other hand, the “allowable lower limit” is a lower limit SOC that causes performance problems such as characteristic deterioration due to overdischarge of the battery 16 when discharging continues further. Since the SOC below the allowable lower limit is a discharge prohibited area called a DCIH area, it is necessary to prevent the SOC from decreasing below the allowable lower limit, which is the upper limit of this area.

  A control center SOC is set between the allowable upper limit and the allowable lower limit. The setting means sets the control center SOC to a value between the allowable lower limit and the allowable upper limit, for example, around 60%. When the control center SOC is set, the charge / discharge request means 62 calculates charge / discharge request power according to the difference between the current SOC of the battery 16 and the control center SOC, and the charge / discharge request power is calculated for the battery 16. A charge / discharge request is made so that the current SOC approaches the control center SOC for output or input.

  Moreover, the control part 36 has set the dischargeable electric power Wout from the battery 16 in driving | running | working according to SOC. FIG. 5 is a diagram illustrating an example of the relationship between the SOC of the battery, the chargeable power Win, and the dischargeable power Wout in the system of FIG. 2 at normal times and when the first voltage sensor fails. As shown in FIG. 5, the dischargeable power Wout from the battery 16 becomes a constant value W1 within a predetermined SOC range in which the SOC is the upper limit of the allowable upper limit A (for example, 80%) as the normal Wout. The dischargeable power Wout gradually decreases (for example, linearly along the straight line L1) when the SOC is equal to or less than a certain value B, so that Wout becomes 0 at the allowable lower limit C of the SOC. Note that “running” means “EV running” in which the second motor generator 18 is driven by the electric power of the battery 16 while the engine 12 is stopped and the wheels 24 are driven by the power, and the power of the engine 12 is This includes both cases of “HV traveling” in which the wheels 24 are driven using the power of the second motor generator 18 (the same applies hereinafter).

  The control unit 36 sets the rechargeable power Win charged to the battery 16 based on the SOC based on the regenerative power from the traveling second motor generator 18. That is, as shown in FIG. 5, as the normal Win, the rechargeable power Win from the battery 16 is constant within a predetermined SOC range in which the SOC is the lower limit of the allowable lower limit C (for example, 20%). The absolute value of the rechargeable power Win is gradually decreased (for example, linearly along the straight line L2) when the SOC is equal to or greater than a certain value D, and Win is set to 0 at the allowable upper limit A of the SOC.

  The controller 36 controls the motor generators 14 and 18 so that the charge / discharge power of the battery 16 falls within a control range determined by the dischargeable power Wout and the chargeable power Win. Specifically, when the discharge power during travel from battery 16 exceeds dischargeable power Wout, control unit 36 suppresses the power consumption of one or both of motor generators 14 and 18, or each motor generator The power generation amount of one or both of 14 and 18 is increased. On the other hand, when the absolute value of the charging power to the battery 16 exceeds the absolute value of the rechargeable power Win, the control unit 36 suppresses the power generation amount of one or both of the motor generators 14 and 18, or Increase the power consumption of one or both of the motor generators 14,18.

  Further, the control unit 36 monitors the voltage of the battery 16 by the first voltage sensor 50, and when the terminal voltage of the battery 16 exceeds a predetermined voltage set in advance, the battery 16 is overcharged or the like, and is abnormally high. It determines with it being in the high voltage state which is a voltage, and performs the predetermined battery high voltage process set beforehand. Further, in order to determine this high voltage, in addition to the first voltage sensor 50, a second voltage sensor 52 that detects the voltage on the low voltage side of the DC / DC converter 42 is also used. Double detection is performed. That is, the second voltage sensor 52 is used not only to detect the voltage on the low voltage side in order to perform the boost control of the DC / DC converter 42 but also to detect the voltage of the battery 16. Used to perform battery high-voltage processing when the battery is abnormally high.

  FIG. 6 is a flowchart showing an example of a method for executing battery high voltage processing based on detection values of the first voltage sensor and the second voltage sensor in the system of FIG. In the example of FIG. 6, the first voltage sensor 50 side and the second voltage sensor 52 side have different routines, and the respective routines are executed substantially in parallel with each other. In FIG. 6, steps S10 (step S is simply referred to as S in the following description) to S16 show a routine on the first voltage sensor 50 side. First, in S10, it is determined whether or not the detection voltage VB of the first voltage sensor 50 exceeds a preset threshold voltage Va. If it is determined that the detection voltage VB exceeds (VB> Va), the state of VB> Va is a predetermined time in S12. It is determined whether it has continued.

  If it is determined in S12 that the battery has continued for a predetermined time, it is determined in S14 that the battery 16 is in a high voltage state, the battery high voltage process is executed, and the process returns to the initial process. On the other hand, if the detected voltage VB> Va is not satisfied in S10 or if it is determined that the detected voltage VB> Va is not satisfied in S12 for a predetermined time, it is determined in S16 that the first voltage sensor 50 is normal, Perform normal normal processing. In this case, the process returns to the first process.

  On the other hand, S20 to S24 and S14 in FIG. 6 indicate a routine on the second voltage sensor 52 side. First, in S20, it is determined whether or not the detection voltage VL of the second voltage sensor 52 exceeds a preset threshold voltage Va, and if it is determined that it exceeds, whether or not the state of VL> Va continues for a predetermined time in S22. Determine. If it is determined in S22 that the battery has continued for a predetermined time, it is determined in S24 that the battery 16 is in a high voltage state, the battery high voltage process is executed, and the process returns to the initial process. On the other hand, if the detected voltage VB> Va is not satisfied in S20, or if it is determined that the detection voltage VB> Va is not satisfied for a predetermined time in S22, it is determined that the second voltage sensor 52 is normal, and normal Perform normal processing. In this case, the process returns to the first process. Therefore, in S14, when the detection voltage VB of the first voltage sensor 50 exceeds the threshold value Va and continues for a predetermined time, the detection voltage VL of the second voltage sensor 52 exceeds the threshold value Va and continues for a predetermined time. When at least one case is established, battery high voltage processing is executed.

  As described above, the battery 16 is subjected to double detection of voltage by the two sensors 50, 52 of the first voltage sensor 50 and the second voltage sensor 52. Even when a failure occurs in the sensor 50 (or 52), the battery 16 can be sufficiently protected from overvoltage. However, as described above in the section “Problems to be Solved by the Invention”, the detection accuracy of the second voltage sensor 52 that is the input-side voltage sensor is normally set to the detection accuracy of the battery 16 voltage. It is not required to be as high as the detection accuracy of the one voltage sensor 50. For this reason, when the first voltage sensor 50 fails, it becomes difficult to detect the voltage of the battery 16 with high accuracy, so that the overvoltage of the battery 16 can be effectively avoided, that is, while the overvoltage protection of the battery 16 is effectively performed, the vehicle There is room for improvement in terms of enabling continuous running.

  In the present embodiment, in order to eliminate such inconvenience, as shown in FIG. 3, the controller 36 includes a first sensor abnormality processing unit 66, a second sensor abnormality processing unit 68, Sensor abnormality processing means 70. The first sensor abnormality processing means 66 acquires the detected value of the voltage of the battery 16 from the second voltage sensor 52 when it is determined that an abnormality has occurred in the first voltage sensor 50 due to a failure or the like, The control center SOC (FIG. 4 (A)) is changed to another control center SOC (FIG. 4 (B)) lower than the normal control center SOC when there is no abnormality in each of the voltage sensors 50, 52, and 54. To do. In this case, the control center SOC is changed so that the control allowable upper limit E is lower than the SOC allowable upper limit indicated by A in FIG. 5 (E <A). For example, in SOC, A is 80% and E is 50%. The control center SOC at the time of failure of the first voltage sensor 50 is set lower than the allowable upper limit E for control. For this reason, even when the first voltage sensor 50 suddenly fails, it is possible to prevent the battery 16 from immediately becoming a high voltage.

  Further, the first sensor abnormality time processing means 66 (FIG. 3) is configured to charge electric power Win that is chargeable / dischargeable electric power to the battery 16 when the abnormality of the first voltage sensor 50 is detected or when the vehicle travels. The dischargeable power Wout is set lower than the normal Win and Wout, respectively. For example, as shown in FIG. 5, the first sensor abnormality processing unit 66 determines the maximum value of Wout at the time of normal operation as the maximum value of Wout during traveling after the abnormality detection of the first voltage sensor 50 or after the abnormality detection. Set to W3, which is lower than the value W1. Further, the Wout during traveling in this case gradually decreases when the SOC is a certain value or less (for example, linearly along the straight line L1) so that the Wout becomes 0 at the allowable lower limit C of the SOC.

  In this case, the control unit 36 also sets the absolute value of the rechargeable power Win charged to the battery 16 based on the regenerative power from the running second motor generator to the absolute value of the normal Win. It is assumed that W4 is lower than the maximum value W2. Further, the absolute value of Win in this case gradually decreases when the SOC exceeds a certain value (for example, linearly along a straight line L3 different from the straight line L2), and Win is 0 at the allowable upper limit E in the control of the SOC. To be.

  Note that whether or not a failure has occurred in the first voltage sensor 50 is determined using, for example, a dual monitoring system having two cell voltage sensors that detect the same battery cell of each battery cell constituting the battery 16. In this case, if a difference occurs between the detection voltages of the two cell voltage sensors, if the difference is greater than or equal to a preset threshold value, or if the difference is not 0, the first voltage sensor 50 has failed. judge. In addition, whether or not a failure has occurred in the first voltage sensor 50 is determined by comparing three detected voltages of the first voltage sensor 50, the second voltage sensor 52, and the third voltage sensor 54. When the detected voltage of the first voltage sensor 50 is different from the detected voltages of the second voltage sensor 52 and the third voltage sensor 54 that are the remaining voltage sensors, it is determined that a failure has occurred in the first voltage sensor 50. Note that it is possible to determine that a failure has occurred in the first voltage sensor 50 only by comparing the detected voltages of the three sensors 50, 52, and 54. Moreover, it can also be determined that a failure has occurred in the first voltage sensor 50 when the voltage of each block of the battery 16 is detected by two block voltage sensors and the detected voltages are different from each other.

  Further, the first sensor abnormality time processing means 66 generates the battery 16 by the power generation of the first motor generator 14 driven by the operation of the engine 12 when the abnormality of the first voltage sensor 50 is detected or after the abnormality is detected. When charging, the maximum value of the chargeable / dischargeable power Win, Wout for the battery 16 is maintained as it is, that is, the same as in the normal time. In plug-in hybrid vehicles, electric vehicles, and the like, in a configuration that allows external charging of the battery 16 by an external power source, the first sensor abnormality processing unit 66 detects or detects abnormality of the first voltage sensor 50. When the battery 16 is charged from an external power source later when the vehicle and the engine are stopped, the maximum values of the chargeable / dischargeable powers Win and Wout for the battery 16 can be maintained as they are, that is, the same as in normal times.

  The second sensor abnormality processing unit 68 (FIG. 3) stops the operation of the DC / DC converter 42 when it is determined that an abnormality has occurred in the first voltage sensor 50 and the second voltage sensor 52. The terminal voltage of the battery 16 is acquired from the third voltage sensor 54. In this case, the DC / DC converter 42 turns on the switching of the positive side switching element S1 out of the two switching elements S1 and S2, and stops the switching operation with the negative side switching element S2 turned off. Let Thereby, the battery 16 side voltage VL of the DC / DC converter 42 and the inverters 38 and 40 side voltage VH become equal (VL = VH), and the third voltage sensor 54 can detect the voltage VB of the battery 16. Become. In this state, power can be supplied from the inverters 38 and 40 to the battery 16, and the generated power when the second motor generator 18 is regenerated can be supplied to the battery 16.

  Further, the second sensor abnormality processing means 68 (FIG. 3) executes a preset battery high voltage process when the detection voltage of the third voltage sensor 54 exceeds a preset threshold value. For this reason, as the backup performance of the battery 16 voltage monitoring, it is possible to ensure the same level of performance as when the second voltage sensor 52 is normal.

  Further, the third sensor abnormality processing means 70 (FIG. 3) determines that the abnormality has occurred in all of the first voltage sensor 50, the second voltage sensor 52, and the third voltage sensor 54, and the system relay 48 Are turned off, and charging and discharging of the battery 16 are stopped.

  In addition to the first voltage sensor 50, whether or not an abnormality has occurred in the second voltage sensor 52 is determined by comparing the detected voltages of the second voltage sensor 52 and the third voltage sensor 54. . In addition, it is possible to specify a sensor in which an abnormality has occurred among the second voltage sensor 52 and the third voltage sensor 54. Based on the signal indicating the specification, the control unit 36 determines whether or not to execute the second sensor abnormality processing unit 68 or the third sensor abnormality processing unit 70.

  According to the rotating electrical machine drive system 30 that is such a vehicle power storage unit protection system, when the first voltage sensor 50 that detects the voltage of the battery 16 detects an abnormality, the first sensor abnormality processing unit 66 performs the second voltage operation. Since the detected value of the voltage of the battery 16 is acquired from the sensor 52, the voltage of the battery 16 can be monitored by the detected value of the second voltage sensor 52. For this reason, when the detected voltage is abnormally high voltage, battery high voltage processing, which is preset specific processing, can be performed. Further, the second motor generator 18 that is a traveling motor can be driven using a voltage obtained by boosting the voltage of the battery 16, and the vehicle can be continuously traveled using the second motor generator 18. Further, the first sensor abnormality time processing means 66 makes the current control center SOC lower than the normal control center SOC. For this reason, it is possible to effectively suppress the SOC of the battery 16 from exceeding the allowable upper limit even though the second voltage sensor 52 that does not require high voltage detection accuracy during normal use is used for voltage detection of the battery 16. For example, if the control center SOC is set lower than E in FIG. 5 (on the left side in FIG. 5), even if the detection error of the second voltage sensor 52 is large and power is supplied to the battery 16 during regeneration, It is possible to effectively prevent the SOC from exceeding the allowable upper limit A (FIG. 5), and it is possible to effectively prevent the overvoltage of the battery 16.

  Further, the SOC of the battery 16 greatly affects the voltage of the battery 16. For this reason, even when an abnormality occurs in the first voltage sensor 50 that detects the voltage of the battery 16, the vehicle can continuously travel while avoiding the overvoltage of the battery 16. As described above, according to the present embodiment, even when an abnormality occurs, such as when the first voltage sensor 50 that detects the voltage of the battery 16 fails, the vehicle can continue to travel while avoiding the overvoltage of the battery 16. The evacuation driving for driving the vehicle to a repair shop or the like can be easily performed, and the traveling distance in that case can be increased.

  In addition, when it is determined that an abnormality has occurred in the first voltage sensor 50, the first sensor abnormality processing unit 66 sets the current control center SOC to be lower than the normal control center SOC, and first When the voltage sensor 50 detects an abnormality or when the vehicle travels, the maximum value of the chargeable / dischargeable power Win, Wout for the battery 16 is reduced below the maximum value of the normal chargeable / dischargeable power Win, Wout, respectively. . For this reason, even when the first voltage sensor 50 is abnormal, the use of the second voltage sensor 52, which does not require high voltage detection accuracy during normal operation, can avoid the overvoltage of the battery 16 and the time when the use of the battery 16 is not limited. It can be lengthened, and rapid changes in the running performance of the vehicle can be suppressed.

  In the same case, when the battery 16 is charged when the abnormality of the first voltage sensor 50 is detected or after the abnormality is detected, the maximum values of the chargeable / dischargeable powers Win and Wout for the battery 16 are maintained as they are. . For this reason, since charging / discharging electric power is not restrict | limited at the time of charge in a vehicle stop state, charging efficiency can be made high. Even when the maximum values of the chargeable / dischargeable powers Win and Wout are increased in this way, the vehicle is stopped, so even if the detection error of the second voltage sensor 52 increases, a problem occurs in the running performance of the vehicle. There is nothing.

  In addition, the rotating electrical machine drive system 30 stops the operation of the DC / DC converter 42 when the first voltage sensor 50 and the second voltage sensor 52 are determined to be abnormal, and the third voltage sensor 54 A second sensor abnormality time processing unit 68 is provided that acquires a voltage between terminals of the battery 16 and executes a preset battery high voltage process when the detected voltage exceeds a preset threshold value. For this reason, even when the abnormality of the second voltage sensor 52 occurs, the voltage of the battery 16 can be monitored by the detection value of the third voltage sensor 54, so that the overvoltage of the battery 16 can be avoided. Further, the second motor generator 18 can be driven using the voltage of the battery 16, and the vehicle can be continuously driven using the second motor generator 18. As described above, according to the present embodiment, even when an abnormality occurs, such as when the second voltage sensor 52 that detects the voltage on the low voltage side of the DC / DC converter 42 has failed, the vehicle 16 avoids overvoltage of the battery 16. Can be continued. The third voltage sensor 54 can ensure backup performance for monitoring the battery 16 voltage. Moreover, since the switching of the DC / DC converter 42 is stopped when the second voltage sensor 52 fails, the heat generation of the DC / DC converter 42 can be greatly reduced.

  In addition, the rotating electrical machine drive system 30 turns off the system relay 48 when it is determined that an abnormality has occurred in all of the first voltage sensor 50, the second voltage sensor 52, and the third voltage sensor 54, and Since the third sensor abnormality processing means 70 for stopping charging and discharging is provided, power supply to the battery 16 can be stopped. For this reason, an increase in the voltage of the battery 16 can be prevented. That is, when the battery 16 is at a high voltage, there is a possibility that the SOC of the battery 16 is high. However, since the increase in the SOC can be prevented, the increase in the voltage of the battery 16 can also be prevented.

  In the above description, “charging” means that it can be applied in all of various charging modes such as quick charging, charging at 100V, charging at 200V, and the like.

  In the above description, the rotating electrical machine drive system 30 serving as the vehicle power storage unit protection system performs all of the first sensor abnormality processing unit 66, the second sensor abnormality processing unit 68, and the third sensor abnormality processing unit 70. Although the case where it has provided was demonstrated, the electrical storage part protection system for vehicles can be set as the structure provided with the at least 1st sensor abnormality time process means 66 among these process means 66,68,70.

  DESCRIPTION OF SYMBOLS 10 Hybrid vehicle, 12 Engine, 14 1st motor generator (MG1), 16 Battery, 18 2nd motor generator (MG2), 20 Power split mechanism, 22 Drive shaft, 24 Wheel, 26 Output shaft, 28 Reducer, 30 rotation Electric drive system, 32 battery monitoring unit, 34 battery ECU, 36 control unit, 38 first inverter, 40 second inverter, 42 DC / DC converter, 44 first capacitor, 46 second capacitor, 48 system relay (SMR), 50 First voltage sensor, 52 Second voltage sensor, 54 Third voltage sensor, 56 Current sensor, 58 SOC acquisition means, 60 Boost control means, 62 Charge / discharge request means, 64 Setting means, 66 First sensor abnormality processing means , 68 Second sensor abnormality processing means, 70 Third sensor Constantly processing means.

Claims (6)

A power storage unit;
A boost converter that boosts the voltage of the power storage unit;
A drive unit that is supplied with a voltage on the high-voltage side of the boost converter and drives the traveling motor;
A first voltage sensor for detecting a voltage between terminals of the power storage unit;
A second voltage sensor that detects a voltage on a low-voltage side of the boost converter, and the detected voltage is used to control the boost converter;
A third voltage sensor that detects a voltage on a high voltage side of the boost converter, and the detected voltage is used to control the boost converter;
SOC acquisition means for acquiring the current SOC that is the current charge amount of the power storage unit;
Setting means for setting a control center SOC, which is a charge amount serving as a control center when controlling the charge amount of the power storage unit;
Charge / discharge requesting means for making a charge / discharge request of the power storage unit so that the current SOC of the power storage unit approaches the control center SOC;
When it is determined that an abnormality has occurred in the first voltage sensor, the detected value of the voltage of the power storage unit is acquired from the second voltage sensor, and the current control center SOC is set lower than the normal control center SOC. A vehicle power storage unit protection system comprising: a first sensor abnormality processing unit. The power storage unit protection system for a vehicle according to claim 1,
When it is determined that an abnormality has occurred in the first voltage sensor, the first sensor abnormality time processing means sets the current control center SOC to be lower than the normal control center SOC, and the abnormality of the first voltage sensor. A power storage unit protection system for a vehicle, wherein the maximum value of chargeable / dischargeable power for the power storage unit is reduced below the maximum value of chargeable / dischargeable power at the normal time when the vehicle travels at the time of detection or after abnormality detection. The power storage unit protection system for a vehicle according to claim 1,
When it is determined that an abnormality has occurred in the first voltage sensor, the first sensor abnormality time processing means sets the current control center SOC to be lower than the normal control center SOC, and the abnormality of the first voltage sensor. When the vehicle travels at the time of detection or after detection of an abnormality, the maximum value of chargeable / dischargeable power for the power storage unit is decreased below the maximum value of chargeable / dischargeable power at the normal time, and when the abnormality of the first voltage sensor is detected or detected. A power storage unit protection system for a vehicle that maintains the current maximum value of chargeable / dischargeable power for the power storage unit when the power storage unit is charged later when the vehicle is stopped. The vehicle power storage unit protection system according to any one of claims 1 to 3,
When it is determined that an abnormality has occurred in the first voltage sensor and the second voltage sensor, the operation of the boost converter is stopped, the detected value of the voltage of the power storage unit is acquired from the third voltage sensor, and the detected voltage is A power storage unit protection system for a vehicle, comprising: a second sensor abnormality processing unit that executes a preset power storage unit high-pressure process when a preset threshold value is exceeded. The vehicle power storage unit protection system according to any one of claims 1 to 4,
When it is determined that an abnormality has occurred in all of the first voltage sensor, the second voltage sensor, and the third voltage sensor, the apparatus includes a third sensor abnormality processing unit that stops charging and discharging the power storage unit. Power storage unit protection system for vehicles. In the vehicle power storage unit protection system according to any one of claims 1 to 5,
The power storage unit is configured by connecting a plurality of battery blocks having a plurality of battery cells connected in series,
The first voltage sensor has a plurality of block voltage sensors that detect the voltage of each battery block, detects the sum of the voltages of each battery block detected by each block voltage sensor as the voltage across the terminals of the power storage unit,
Each of the second voltage sensor and the third voltage sensor has a detection accuracy lower than the detection accuracy of the first voltage sensor.

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